diff --git a/module/module.json b/module/module.json
index 0dbcc1e..edd1f4b 100644
--- a/module/module.json
+++ b/module/module.json
@@ -5,8 +5,8 @@
     "author": "troygoode, Argonius-Angelus, mattd",
     "url": "https://github.com/mattd/foundryvtt-progress-clocks",
     "manifest": "https://raw.githubusercontent.com/mattd/foundryvtt-progress-clocks/main/module/module.json",
-    "download": "https://github.com/mattd/foundryvtt-progress-clocks/releases/download/v1.5.3/build.zip",
-    "version": "1.5.3",
+    "download": "https://github.com/mattd/foundryvtt-progress-clocks/releases/download/v1.5.4/build.zip",
+    "version": "1.5.4",
     "minimumCoreVersion": "0.7.0",
     "compatibleCoreVersion": "10",
     "compatibility": {
diff --git a/module/scripts/clock.mjs b/module/scripts/clock.mjs
index dccca5c..6b0a802 100644
--- a/module/scripts/clock.mjs
+++ b/module/scripts/clock.mjs
@@ -33,16 +33,6 @@ export class Clock {
         this.theme = theme || 'wallflower_green';
     }
 
-    get flags () {
-        return {
-            clocks: {
-                size: this.size,
-                progress: this.progress,
-                theme: this.theme
-            }
-        };
-    }
-
     increment () {
         const old = this;
         return new Clock({
diff --git a/module/scripts/sheet.mjs b/module/scripts/sheet.mjs
index 55d198d..490b325 100644
--- a/module/scripts/sheet.mjs
+++ b/module/scripts/sheet.mjs
@@ -140,24 +140,18 @@ export class ClockSheet extends ActorSheet {
 
         // Update the tokens
         for (const token of tokens) {
+            const tokenData = {
+                name: actor.name,
+                img: (
+                    `/${Clock.themes[clock.theme]}` +
+                    `/${clock.size}clock_${clock.progress}.png`
+                ),
+                actorLink: true
+            };
             if (foundryVersion.major >= 8) {
-                await token.document.update({
-                    name: actor.name,
-                    img: (
-                        `/${Clock.themes[clock.theme]}` +
-                        `/${clock.size}clock_${clock.progress}.png`
-                    ),
-                    actorLink: true
-                });
+                await token.document.update(tokenData);
             } else {
-                await token.update({
-                    name: actor.name,
-                    img: (
-                        `/${Clock.themes[clock.theme]}` +
-                        `/${clock.size}clock_${clock.progress}.png`
-                    ),
-                    actorLink: true
-                });
+                await token.update(tokenData);
             };
         }
 
diff --git a/module/scripts/systems/dnd5e.mjs b/module/scripts/systems/dnd5e.mjs
index 5e7e819..2053eb9 100644
--- a/module/scripts/systems/dnd5e.mjs
+++ b/module/scripts/systems/dnd5e.mjs
@@ -1,14 +1,6 @@
 export default {
     registerSheetOptions: { types: ["npc"] },
 
-    loadClockFromActor: ({ actor }) => {
-        return {
-            progress: actor.getFlag("clocks", "progress"),
-            size: actor.getFlag("clocks", "size"),
-            theme: actor.getFlag("clocks", "theme")
-        };
-    },
-
     persistClockToActor: ({ clock }) => {
         return {
             data: {
@@ -20,7 +12,7 @@ export default {
                 }
             },
             flags: {
-                clocks: {
+                "progress-clocks": {
                     progress: clock.progress,
                     size: clock.size,
                     theme: clock.theme,
diff --git a/package-lock.json b/package-lock.json
index a7cd8b0..e5fa8d1 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
     "name": "foundryvtt-progress-clocks",
-    "version": "1.5.3",
+    "version": "1.5.4",
     "lockfileVersion": 2,
     "requires": true,
     "packages": {
         "": {
             "name": "foundryvtt-progress-clocks",
-            "version": "1.5.3",
+            "version": "1.5.4",
             "license": "MIT",
             "devDependencies": {
                 "ava": "^4.3.1"
diff --git a/package.json b/package.json
index a34b60a..a9956c0 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
     "name": "foundryvtt-progress-clocks",
-    "version": "1.5.3",
+    "version": "1.5.4",
     "description": "Brings Forged in the Dark style progress clocks to your FoundryVTT games.",
     "main": "module/scripts/init.mjs",
     "scripts": {
diff --git a/test/clock/constructor.mjs b/test/clock/constructor.mjs
index c54691f..6821763 100644
--- a/test/clock/constructor.mjs
+++ b/test/clock/constructor.mjs
@@ -13,3 +13,44 @@ test("sets a default theme when none is provided", t => {
     const clock = new Clock();
     t.assert(clock.theme);
 });
+
+test("sets size to a supported size if supplied an unsupported size", t => {
+    const size = 1;
+    const clock = new Clock({
+        size: size
+    });
+    t.assert(Clock.sizes.indexOf(parseInt(size)) == -1);
+    t.assert(Clock.sizes.indexOf(parseInt(clock.size)) >= 0);
+});
+
+test("sets a default size when none is provided", t=> {
+    const clock = new Clock();
+    t.assert(clock.size);
+});
+
+test("sets the correct progress when provided", t => {
+    const clock = new Clock({
+        progress: 2
+    });
+    t.is(clock.progress, 2);
+});
+
+test("sets progress equal to size if progress is larger than size", t=> {
+    const clock = new Clock({
+        size: 8,
+        progress: 9
+    });
+    t.is(clock.progress, 8);
+})
+
+test("sets progress to zero if no progress is provided", t => {
+    const clock = new Clock();
+    t.is(clock.progress, 0);
+})
+
+test("sets progress to zero if provided progress is less than zero", t => {
+    const clock = new Clock({
+        progress: -1
+    });
+    t.is(clock.progress, 0);
+});
diff --git a/test/clock/decrement.mjs b/test/clock/decrement.mjs
new file mode 100644
index 0000000..c237908
--- /dev/null
+++ b/test/clock/decrement.mjs
@@ -0,0 +1,38 @@
+import test from 'ava';
+
+import { Clock } from "../../module/scripts/clock.mjs";
+
+test("returns a new Clock object", t => {
+    const oldClock = new Clock({
+        progress: 1
+    });
+    const newClock = oldClock.decrement();
+    t.assert(newClock instanceof Clock);
+    t.not(newClock, oldClock);
+});
+
+test("decrements the previous progress by 1", t => {
+    const oldClock = new Clock({
+        progress: 1
+    });
+    const newClock = oldClock.decrement();
+    t.is(newClock.progress, 0);
+});
+
+test("does not alter the previous size", t => {
+    const oldClock = new Clock({
+        size: 4,
+        progress: 1
+    });
+    const newClock = oldClock.decrement();
+    t.is(newClock.size, 4);
+});
+
+test("does not alter the previous theme", t => {
+    const oldClock = new Clock({
+        theme: 'gms_red',
+        progress: 1
+    });
+    const newClock = oldClock.decrement();
+    t.is(newClock.theme, 'gms_red');
+});
diff --git a/test/clock/increment.mjs b/test/clock/increment.mjs
new file mode 100644
index 0000000..cf2c121
--- /dev/null
+++ b/test/clock/increment.mjs
@@ -0,0 +1,38 @@
+import test from 'ava';
+
+import { Clock } from "../../module/scripts/clock.mjs";
+
+test("returns a new Clock object", t => {
+    const oldClock = new Clock({
+        progress: 1
+    });
+    const newClock = oldClock.increment();
+    t.assert(newClock instanceof Clock);
+    t.not(newClock, oldClock);
+});
+
+test("increments the previous progress by 1", t => {
+    const oldClock = new Clock({
+        progress: 1
+    });
+    const newClock = oldClock.increment();
+    t.is(newClock.progress, 2);
+});
+
+test("does not alter the previous size", t => {
+    const oldClock = new Clock({
+        size: 4,
+        progress: 1
+    });
+    const newClock = oldClock.increment();
+    t.is(newClock.size, 4);
+});
+
+test("does not alter the previous theme", t => {
+    const oldClock = new Clock({
+        theme: 'gms_red',
+        progress: 1
+    });
+    const newClock = oldClock.increment();
+    t.is(newClock.theme, 'gms_red');
+});